x86: consolidate header guards

This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h
index 16a31e2..38741ac 100644
--- a/include/asm-x86/e820.h
+++ b/include/asm-x86/e820.h
@@ -1,5 +1,5 @@
-#ifndef __ASM_E820_H
-#define __ASM_E820_H
+#ifndef ASM_X86__E820_H
+#define ASM_X86__E820_H
 #define E820MAP	0x2d0		/* our map */
 #define E820MAX	128		/* number of entries in E820MAP */
 
@@ -140,4 +140,4 @@
 #define HIGH_MEMORY	(1024*1024)
 #endif /* __KERNEL__ */
 
-#endif  /* __ASM_E820_H */
+#endif /* ASM_X86__E820_H */